Field of the Invention
The present invention relates to an image forming system, an image forming apparatus, and a skew correction method.
Description of the Related Art
Commonly, an image forming apparatus using an electrophotographic process technology (such as a printer, a copying machine, and a facsimile) forms an electrostatic latent image by irradiating (exposing) a charged photoconductor with (to) laser light based on image data. Then, the electrostatic latent image is visualized by supplying toner from a developing device to a photoconductor drum on which the electrostatic latent image is formed, and a toner image is formed accordingly. Thereafter, the toner image is directly or indirectly transferred to a sheet, and the toner image is formed on the sheet by heating and pressurizing with a fixing nip to fix the image.
Furthermore, an image forming system, in which a sheet feeding device which feeds a continuous sheet, such as a continuous roll sheet or a folded sheet, (hereinafter, referred to as a long sheet) and a sheet discharging device which stores the long sheet on which a toner image formed by the image forming apparatus are respectively connected with a pre-stage and a post-stage of the above image forming apparatus, has been in practical use.
JP 2012-116153 A discloses a technique for reducing waste sheets without a burden on an operator when image formation is resumed after a continuous paper is reset due to a jam or the like during both-side image formation. In the technique disclosed in JP 2012-116153 A, when a both-side print job is interrupted due to generation of a jam during execution of the image formation related to the both-side image formation job and then the printing is resumed, a second engine starts printing related to a one-side print job with respect to the reset continuous sheet, and when the number of pages related to the started one-side print job becomes the number of pages or less on a conveyance path between a first engine and the second engine, the printing related to the interrupted both-side print job is resumed.
Incidentally, in the above image forming system, a sheet jam, in which a long sheet being conveyed on a sheet conveyance path of the long sheet is jammed during an image forming operation to form a toner image on the long sheet, may occur. In this case, after the image forming operation is suspended and it is confirmed that a sheet jam occurring part, where the sheet jam occurs and the operation is suspended, is removed by a user, recovery to resume the suspended image forming operation is executed. Thus, occurrence of a sheet jam causes a problem that productivity is deteriorated during suspending the image forming operation.
In the technique disclosed in JP 2012-116153 A, a process, in which a jammed part is removed and a continuous paper is reset after the jam occurs, is required, and which causes a problem similar to the above problem.